1. Field of the Invention
This invention relates to a magnetic voltage and/or current reference that provides a stable, precise and virtually radiation impervious voltage and/or current which may be applied to missile guidance systems, accelerometers, digital-to-analog and analog-to-digital converters, gyrotorque converters, and other precision electronics that may operate within a hostile, radiation filled environment, such as that produced by space radiation or nuclear fusion/fission apparatus.
2. Background Art
Systems are known by which to generate an accurate DC or AC reference voltage and/or current. However, contemporary systems typically employ semiconductor, as opposed to magnetic, methods. Although magnetic references pre-date semiconductor technology, such magnetic references were widely abandoned in early 1960's due to the improvement in semiconductor processing and the development of the integrated circuit.
Precision semiconductor references rely on the zener and/or avalanche characteristics of a PN junction to obtain the largest portion of a reference voltage. In order to obtain an overall low temperature coefficient, an additional PN junction is placed in series with the zener junction to provide a low sensitivity to temperature within a very small volume. The aforementioned precision junction references are often integrated in a monolothic linear integrated circuit chip using DC current sources and amplifiers/buffers to provide a low impedance voltage or current to other semiconductor electronics.
However, because of the inherent limitations in the properties of semiconductor materials (e.g. the reduction of semiconductor lifetime due to radiation damage), it is difficult to maintain high precision when employing this type of semiconductor reference within a hostile environment. Moreover, errors caused by the zener voltage shift can be propagated to instrument parameters whereby to cause degradation of overall system accuracy. Hence, it would be desirable to find an alternative to the semiconductor precision reference by using non-semiconductor (e.g. magnetic) materials.
Reference may be made to the following United States Patents for examples of magnetic based circuits which are adapted to measure an external magnetic field:
2,388,070 Oct. 30, 1945 PA0 3,159,785 Dec. 1, 1964 PA0 4,059,796 Nov. 22, 1977